package chapter01;

import java.util.Scanner;

public class ComputeArea {
    public static void main(String[] args) {
        Scanner in = new Scanner(System.in);

        System.out.printf("input radius:");
        double radius = in.nextDouble();
        double area = radius * radius * Math.PI;

        System.out.println("Area is:" + area);
    }
}

class s{
    public static void main(String[] args) {
    }
}
